IN THE MONTH OF FEBRUARY, 1842. 183 
case, it partially obstructs the progress of the normal current. This temporary retarda- 
tion only gives it accumulated energy, and it is soon reinstated with unwonted violence. 
When the rarefaction is considerable, this rush of air upon the last half of a storm is not 
generally in the precise direction of the upper current, but more northerly; this air being 
the denser. Our southerly wind is thus supplanted by a violent north-wester. We have 
thus a great rarefaction and elevation of the temperature under a south or south-east 
wind with rain, extending over a large territory. This may be called the third phase of 
the storm, although it differs from the second only in intensity. There is now a gene- 
ral rush of heavier air to fill this void. This rush is chiefly from the north; but an 
independent cause, that which imparts direction to the upper current, would give usa 
west wind. Under these two forces the resulting current is chiefly north-west, but 
every where upon the borders, the tendency will be inward. The air thus flowing 
inward towards a central area, forces upwards the warmer ait which rises in the middle, 
and being cooled by elevation, discharges a greater quantity of rain. The currents 
moving centrally from every point of the compass, interfere with each other, and pursue 
their routes spirally inward. We have thus a species of rotation, which, in the centre of 
the storm may have a destructive violence, as at Mayfield, F ebruary 4, 1842. This is 
the fourth phase, and is the case of a violent storm fully organized. This west or north- 
west wind carries the storm off from a fixed locality, and it is thus transferred succes- 
sively to points farther and farther east. But this action cannot continue indefinitely. 
There is a cause in operation which will soon terminate its violence. This westerly 
wind travels more rapidly than the easterly. The rarefaction at the centre of the storm 
is a cause which acts equally upon both winds; but the one is opposed to the upper cur- 
rent, and the other nearly coincides with it: hence the one is accelerated, and the other 
retarded. The result is, that at successive points, farther and farther east, the same storm 
(after the north-west wind has begun to blow with great violence) has a less duration; 
the thermometer rises to a less height, the barometer has a smaller oscillation, and thus 
at a point far eastward, the oscillation becomes nearly extinct, and the only peculiarity 
observed in the wind is a stronger westerly current succeeding a calm. This is the fifth 
and final phase of the storm. 
It appears to me, that if the course of investigation adopted with respect to the two 
storms of Iebruary, 1842, were systematically pursued, we should soon have some settled 
principles in meteorology. If we could be furnished with two meteorological charts of the 
United States, daily, for one year, charts showing the state of the barometer, thermometer, 
winds, sky, &c., for every part of the country, it would settle for ever the laws of storms. 
No false theory could stand against such an array of testimony. Such a set of maps would 
be worth more than all which has been hitherto done in meteorology. Moreover, the 
subject would be well nigh exhausted. But one year’s observation would be needed ; 
the storms of one year are probably but a repetition of those of the preceding. Instead, 
then, of the guerilla warfare which bas been maintained for centuries with indifferent 
success, although at the expense of great self-devotion on the part of individual chiefs, is 
it not time to embark in a general meteorological crusade? A well arranged system of 
